Heretofore various airflow measuring devices have been employed to measure the bulk flow of air or gas streams particularly in conduits, such as single point sensing Pitot-static tubes, velometers and thermal hot wire anemometer probes or multi-point sensing devices like the airflow measuring stations illustrated in U.S. Pat. No. 3,685,355 and No. 3,733,900 issued to Kenneth W. DeBaun, U.S. Pat. No. 3,981,193 and No. 4,036,054 to Roger T. Goulet and U.S. Pat. No. 4,297,900 issued to Robert O. Brandt.
The present invention is an adaptation of the so-called Fechheimer probe described in "Measurement of Static Pressure," Transactions of the ASME (1926), Volume 48, pages 965-977 by C. J. Fechheimer; in "Quantitation of Stack Gas Flow" by C. L. Burton published in the Journal of the Air Pollution Control Association, August 1972, Volume 22, No. 8, pages 631-635; and in the article by Ralph Poole entitled "Aerodynamics for the Heating and Ventilating Engineer" appearing in The Heating and Ventilating Engineer and Journal of Air Conditioning for May 1946 at pages 455-460; and in textbooks such as Fundamentals of Temperature Pressure and Flow Measurements, Second Edition, edited by Robert P. Benedict, John Wiley & Sons, page 352. All the latter describe and utilize for one purpose or another the pressure distribution on the surface of a cylinder that is oriented substantially normal to the flow of an air or gas stream.